The present invention is directed to an optical phase shifter.
In optical transmission, it may be desirable to manipulate an optical signal to provide the ability to route certain wavelengths in a multi-wavelength optical signal (e.g., WDM, DWDM, UDWDM, etc.) to a desired destination. One such manipulation is phase shifting. In a multi-wavelength optical signal, if a desired wavelength is phase shifted, while undesired wavelengths are not, that phase shifted wavelength can be isolated from the other wavelengths. The phase shifted wavelength may then be switched or coupled from one waveguide to another or otherwise routed to its desired destination.
It may also desirable to provide a phase shifter capable of introducing a fixed, predetermined phase shift into an optical signal. Alternatively, it may be similarly desirable to provide a phase shifter capable of introducing a selectable phase shift into an optical signal. It is further desirable that such a device be small in size and consume little power.
The present invention is directed to a phase shifter. Such a phase shifter can apply a phase shift to an optical signal passing therethrough. The phase shifter has coaxial first and second waveguides, each having a core defining an optical path therethrough, and which are separated from each other by a predetermined distance. A phase shift element is disposed between the first and second waveguides, and an actuator is coupled to the phase shift element to cause selective movement of the phase shift element between a first position in which an optical signal passing from the first waveguide to the second waveguide passes through the phase shift element, and a second position in which the optical signal does not pass through the phase shift element.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the disclosure herein. The scope of the invention will be indicated in the claims.